1. Field of the Invention
The present invention relates to a DVD video playback system adapted to play back a DVD-Video disk by using a plurality of output devices.
2. Description of the Related Art
In a known DVD video playback system adapted to play back a DVD-Video disk by using a plurality of output devices, the system includes a source device having a DVD drive for reading data from the DVD-Video disk and a plurality of sink devices connected to the source device via a bus or a network, whereby the data read from the DVD-Video disk is transmitted from the source device to each sink device, and each sink device outputs a video image in accordance with the received data (see, for example, PCT Japanese Translation Patent Publication No. 2002-535197).
As a technique associated with such a DVD video playback system, it has been proposed that data transmitted from the source device to each sink device is constructed in the form of a PS (Program Stream) similar to an original PS (in which video data, audio data, subpicture data, etc. are multiplexed) recorded on a DVD-Video disk, and each sink device decodes the received PS into video data, audio data, subpicture data, etc.
In the DVD video playback system including the source device and the plurality of sink devices, it is desirable that the DVD video playback system be capable of playing back a DVD video disk in a similar manner to the manner in which playback is performed by a DVD video playback apparatus according to the DVD-Video standard.
In the DVD video playback apparatus according to the DVD-Video standard, decoding of a program stream (PS) recorded on a DVD-Video disk is performed not such that the PS is simply decoded but such that decoding of the PS is controlled in accordance with various control data recorded on the DVD-Video disk and also in accordance with a playback control operation performed on the DVD video playback apparatus.
This means that if only the PS similar to the original PS read from the DVD-Video disk is transmitted from the source device to each sink device and no other associated control data is transmitted, it is impossible to play back the PS in a similar manner to the manner in which the PS is decoded by the DVD video playback apparatus according to the DVD-Video standard.
In view of the above, it is an object of the present invention to provide a DVD video playback system which includes a source device and a plurality of sink devices, and in which data is transmitted in the form of a PS with a format similar to that of an original PS recorded on a DVD-Video disk from the source device to each sink device thereby making it possible to play back the DVD-Video disk in a similar manner to the manner in which playback is performed in accordance with the DVD-Video standard.
In a case in which the PS including a plurality of streams such as audio streams or the like is sent from the source device to each sink device, each sink device is allowed to, independently of other sink devices, select a desired stream and decode the selected stream. This provides great convenience for users. However, if it is allowed to independently control playback of each sink device, conflict of playback conditions can occur among the sink devices. For example, when the data recorded on the DVD-Video disk includes control data that defines changes in a playback sequence depending on a stream being currently played back, if there is a difference in the decoded and output stream among the sink devices, it is impossible for the source device to definitively determine the following playback sequence.
Thus, it is another object of the present invention to provide a DVD video playback system including a source device and a plurality of sink devices, capable of resolving conflict in playback conditions among the sink devices which can occur when playback of each sink device is independently controlled.